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Alternating Current — Physics STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 SciencePhysicsAlternating Current1 Mark
Question
For two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is not the correct explanation of A.
  3. A is true but R is false.
  4. A is false and R is also false.
Assertion: Capacitor serves as a block for D.C. and offers an easy path to A.
Reason: Capacitive reactance is inversely proportional to frequency.
✓

Answer

  1. Both A and R are true and R is the correct explanation of A.

Explanation:

The capacitive reactance of capacitor is given by,

$\text{X}_\text{C}=\frac{1}{\omega\text{C}}=\frac{1}{2\pi\text{fC}}.$

So this is infinite for D.C. (f = 0) and has a finite value for A.C. Therefore a capacitor blocks D.C. and offers an easy path for A. C.

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